Messages in this thread | | | Date | Wed, 24 Apr 2019 14:34:15 -0700 | From | Davidlohr Bueso <> | Subject | Re: Strange issues with epoll since 5.0 |
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On Wed, 24 Apr 2019, Eric Wong wrote:
>Omar Kilani <omar.kilani@gmail.com> wrote: >> Hi there, >> >> I???m still trying to piece together a reproducible test that triggers >> this, but I wanted to post in case someone goes ???hmmm... change X >> might have done this???. > >Maybe Davidlohr knows, since he's responsible for most of the >epoll changes in 5.0.
Not really, I have not been made aware of any issues until now.
> >> Basically, something???s broken (or at least, has changed enough to >> cause problems in user space) in epoll since 5.0. It???s still broken in >> 5.1-rc5. >> >> It doesn???t happen 100% of the time. It???s sort of hard to pin down but >> I???ve observed the following: >> >> * nginx not accepting connections under load >> * A java app which uses netty / NIO having strange writability >> semantics on channels, which confuses netty / java enough to not >> properly flush written data on the socket. >> >> I went and tested these Linux kernels: >> >> 4.20.17 >> 4.19.32 >> 4.14.111 >> >> And the issue(s) do not show up there. >> >> I???m still actively chasing this up, and will report back ??? I haven???t >> touched kernel code in 15 years so I???m a little rusty. :)
A bisection and/or workload that triggers the issue would be great to see what's going on.
Thanks, Davidlohr
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